I have a list of constants (I'm using them as an enum), some are define statements, and some are just global variables.

Where am I suppose to put them in the MVC framework so I can use them for both my model and my controller that needs to reference it?

I'd rather not stick it into config/constants.php since they shouldn't be called except for by this model and the controllers that use it.

Edit 1: Clarification

To be more specific, I have my message_model model and it has a bunch of constants that I need that are stored in message_model_constants.php. Where should I put message_model_constants.php and is there a way to have it automatically included by the controller that loads message_model when message_model is not (and I don't want it to be) auto-loaded.

Edit 2:

I really don't want to have the constants auto-loaded except for when I use the model